The goal of this proposal, is to explore the mechanisms of mammary cancer induction by daunomycin and the mechanisms of cancer prevention offered by Alpha-tocopherol. 1. To investigate and compare the enzyme activities which generate free-radical intermediates during the metabolism of daunomycin in isolated mammary epithelial cells and hepatocytes. These enzymes include NADPH cytochrome (P-450) reductase (E.C.1.6.2.4), NADH-oxidoreductase (E.C.1.6.99.3) and xanthine oxidase. In addition, enzyme activities divert the metabolism of daunomycin from free radical generation will also be investigated and compared in the isolated cells. These activities include carbonyl reductase(s) and NAD(P)H quinone reductase(s) (E.C.1.6.99.2). The effect of Alpha-tocopherol on the enzymic activities, specifically, xanthine oxidase and the quinone reductase will be determined. 2. To quantitate daunomycin-induced superoxide anion, hydroxyl radical, hydrogen peroxide, lipid hydroperoxide, and oxygen consumption in the isolated mammary epithelial cells. The influence of cellular reduced glutathione (GSH) and its regulating enzymes concerning the formation of H2O2 and OH will be studied. The protective effect of Alpha-tocopherol on the lipid peroxidation, DNA breaks and protein alkylation caused by radicals, hydrogen peroxide and daunomycin (or metabolites) will be evaluated. 3. To determine the time course of the biochemical reactions and damages induced by daunomycin, and the relationship between Alpha-tocopherol concentration and the formation of daunomycin induced oxidative species in isolated cells. 4. To determine the dose response relationship between the protective effect of Alpha-tocopherol and daunomycin induced cellular damages and carcinogenesis in vivo.